This invention relates to security locks for doors and, in particular, security locks capable of engaging the door with a door frame on opposite sides of the frame.
Security at homes and at businesses has become an increasing concern due to high levels of break-ins and home invasions. One of the most common security measures is a deadbolt lock for exterior doors. These locks are mounted in apertures bored in the door adjacent the frame on the side opposite the hinges. The deadbolt lock includes a bolt which slidably extends from the door and engages a bore in the frame of the door, typically surrounded by a plate. While these locks do provide significantly improved security compared with knob-mounted locks, they do not provide an adequate degree of security for many doors, particularly wooden doors or steel doors with wood frames, if an intruder attempts to kick in the door. Either the door itself or the frame may fail if subjected to a hard blow from an intruder""s foot.
It has been known to provide a bolt and lock for doors which includes upper and lower bolts engaging a frame or the like above and below the door. For example, a device of this nature is found in U.S. Pat. No. 2,787,154. The device in this patent is activated by a rack mechanism in conjunction with knobs.
U.S. Pat. No. 4,288,944 shows a mechanism generally similar to the patent above except that the bolts move horizontally into the frame. A similar device is shown in U.S. Pat. No. 4,088,353.
U.S. Pat. No. 5,524,941 shows a multipoint door lock assembly.
U.S. Pat. No. 3,991,595 shows a locking arrangement for doors employing sliding bolts, but it is not well adapted for retrofitting existing doors.
Bolts engageable with the top and bottom of the door, however, have not been commonly used on residential or business doors. One reason for this is that prior art devices of the general type have not been convenient to lock and unlock. They may involve the use of separate cranks or levers which may not even be accessible from the outside of the door. In addition, earlier devices are often not convenient to retrofit onto an existing standard door and deadbolt lock.
It is an object of the invention to provide an improved security lock for a door which substantially increases the level of security compared with a standard deadbolt lock.
It is also an object of the invention to provide an improved security lock for a door which engages the frame of the door adjacent opposite edges of the door and which is convenient to use.
It is a further object of the invention to provide an improved security lock for doors which engages the door to the frame adjacent the top and bottom thereof, which can be easily engaged or disengaged from both sides of the door and which is easy to install.
It is a still further object of the invention to provide an improved security lock for doors which can engage the door with the top and bottom of the frame and which does not require additional large apertures to be bored through the door apart from standard apertures for a knob and a deadbolt lock.
It is a still further object of the invention to provide an improved security lock which can be readily installed onto an existing standard door equipped with a standard deadbolt lock.
There is provided, according to one aspect of the invention, a security lock for a door having a top, a bottom, a frame and a deadbolt lock. The security lock includes a first bolt mountable on the door so as to extend to a first edge thereof to selectively engage the frame near the first edge of the door. There is a second bolt mountable on the door so as to extend to a second edge thereof and selectively engage the frame near the second edge of the door. A mechanism operatively connects the first bolt and the second bolt to the deadbolt lock. When the deadbolt lock is engaged, the first bolt and the second bolt engage the frame. When the deadbolt lock is disengaged, the first bolt and the second bolt are disengaged from the frame.
There is provided, according to another aspect of the invention, a security apparatus including a door having a top, bottom, a frame and a deadbolt lock. There is a security lock which includes a first bolt mountable on the door so as to extend to the top thereof to selectively engage the frame near the top of the door. A second bolt is mountable on the door so as to extend to the bottom thereof to selectively engage the frame near the bottom of the door. A mechanism operatively connects the first bolt and the second bolt to the deadbolt lock. When the deadbolt lock is engaged, the first bolt and the second bolt engage the frame. When the deadbolt is disengaged, the first bolt and the second bolt are disengaged from the frame.